Loss of the insular ribbon sign

The loss of the insular ribbon sign refers to a loss of definition of the gray-white interface in the lateral margin of the insular cortex ("insular ribbon") and is considered an early CT sign of MCA infarction.

The insular cortex is more susceptible to ischaemia following MCA occlusion than other portions of the MCA territory because it has the least potential for collateral supply from the anterior cerebral and posterior cerebral arteries.